NAME

SYNOPSIS

DESCRIPTION

The
strcasecmp()
function performs a byte-by-byte comparison of the strings
s1
and
s2,
ignoring the case of the characters.
It returns an integer
less than, equal to, or greater than zero if
s1
is found,
respectively, to be less than, to match, or be greater than
s2.

The
strncasecmp()
function is similar, except that it compares
no more than
n
bytes of
s1
and
s2.

RETURN VALUE

The
strcasecmp()
and
strncasecmp()
functions return
an integer less than, equal to, or greater than zero if
s1
is, after ignoring case, found to be
less than, to match, or be greater than
s2,
respectively.

ATTRIBUTES

For an explanation of the terms used in this section, see
attributes(7).

Interface

Attribute

Value

strcasecmp(),
strncasecmp()

Thread safety

MT-Safe locale

CONFORMING TO

4.4BSD, POSIX.1-2001, POSIX.1-2008.

NOTES

The
strcasecmp()
and
strncasecmp()
functions first appeared in 4.4BSD, where they were declared in
<string.h>.
Thus, for reasons of historical compatibility, the glibc
<string.h>
header file also declares these functions, if the
_DEFAULT_SOURCE
(or, in glibc 2.19 and earlier,
_BSD_SOURCE)
feature test macro is defined.

The POSIX.1-2008 standard says of these functions:

When the
LC_CTYPE
category of the locale being used is from the POSIX locale,
these functions shall behave as if the strings had been converted
to lowercase and then a byte comparison performed.
Otherwise, the results are unspecified.

SEE ALSO

COLOPHON

This page is part of release 4.13 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.